Cellular plastic materials which are condensation products of hydroxy containing fatty acid glycerides and arylene dhsocyanates



United States Patent CELLULAR PLASTIC MATERIALS WHICH ARE CONDENSATIONPRODUCTS OF HYDROXY CONTAINING FATTY ACID GLYCERIDES AND ARYLENEDIISOCYANATES Stanley R. Detrick, Wilmington, and Eric Barthel, Jr., NewCastle, Del., assignors to E. I. du Pont de N ernours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationMarch 3, 1953, Serial No. 340,168

8 Claims. (Cl. 260--2.5)

This invention relates to new and valuable cellular plastic materials,and more particularly to cellular plastic materials which arecondensation products of hydroxy-containing fatty acid glycerides andarylene diisocyanates that have been further reacted wtih water.

Cellular plastic products or plastic foams have been prepared in whichisocyanates are used as one of the reactants-see, for instance, GermanPlastics Practice, by De Bell, Goggin and Gloor, 1946, pp. 316, 463-465.In these products the cellular materials are prepared from alkyd resinswhich contain free carboxy groups. Products of this nature which haveappeared on the market are not as resistant to destructive mechanicalaction as could be desired, since by compression, flexing or impact theyare readily deformed or destroyed.

It is an object of the present .invention to produce from readilyavailable chemicals cellular plastic materials of improved propertieswhich are in general useful where cellular plastics are of value andparticularly as insulation material. A further object is to providecellular plastic materials which have high insulation value and lowapparent density. A still further object of the invention is to providecellular plastic material which can be readily formed in the place whereit is to be used, and therefore need not be premolded or prepared underspecial reaction conditions.

The cellular plastic material of this invention is preferably producedby reacting an arylene diisocyanate with an amount of a fatty acidtriglyceride having an hydroxyl number not materially less than 49, suchthat the ratio of the number of hydroxyl groups contained in the fattyacid triglyceride to the number of isocyanate groups in the arylenediisocyanate is greater than 0.45 to 2 but not more than 0.95 to 2(which leaves from 52.5% to 77.5% of the isocyanate groups unreacted),and mixing the reaction product with an amount of water that issubstantially stoichiometn'cally equivalent to the unreacted isocyanategroups (NCO) in the mass. In general this amount of water will be withfrom 0.4 to 1.7 mols per mol of arylene diisocyanate employed. Bystoichiometrically equivalent is meant one mol of water per twoisocyanate (NCO) groups. The fatty acid triglycerides may be thenaturally occurring oils containing the ricinoleic acid glyeeride or theblown drying oils commonly referred to in "the trade as heavy bodiedoils such as blown linseed tung, poppyseed, hempseed, soya oil, etc.

These products are prepared in two steps. In the first step adiisocyanateis reacted with a hydroxy containing fatty acid triglyceridetojform what may be called a prepolymer. The proportion of diisocyanateto fatty acid glyceride should besuch that when not more than 47.5% ofthe total isocyanate groups in the diisocyanate have reactedwith thehydroxyl groups on the fatty acid radicals, there are, no longer anyremaining available bydroxyl groups. Thisleaves then more than halfofthe original isocyanate groups available for further reaction. Thus itis postulated thatin the case of, for example,

" 2,787,601 I Patented Apr. 2, 1957 castor oil, each of the hydroxygroups on the three fatty acid chains attached to the glyceride isreacted with one of the isocyanate groups on the organic diisocyanatewith the formation of a urethane link. This then gives a fatty acidglyceride having attached to each fatty acid chain an isocyanate groupwhich is free to react with any reactive hydrogens plus unreacteddiisocyanate. Using 2,4- toly-lene diisocyanate as an example, one canpostulate the following idealized structural formula:

H C 2h Ha N00 m Ha (CH:)sOHa This product is then mixed with water and asmall amount of tertiary amine catalyst to accelerate the reaction. Thereaction mass immediately begins to foam 'due to the reaction of theunreacted isocyanate groups with the water to form CO2 and substitutedureas. if the foam is confined in a for-med space then the foam willfill up that space and in a relatively short time will cure at roomtemperature to a firm, non-brittle sponge that is resistant to damage bycompression.

By using the amount of isocyanate as given above, so that the ratio ofthe number of --OH groups to -NCO groups is between 0.45 to 2 and 0.95to 2, there is never enough fatty acid glyceri-de to completelyreactwith one isocyanate group on all of the aromatic organic diisocyanate.On the other hand, at the lower end of the range there is never toolarge 'an excess of organic diisocyanate. When the ratio is greater than0.95 to 2, a soft, pliable plastic material is obtained which is moredense, that is,'has too small pore size and a lower softening point thanis usually desirable where the material is to be worked as hereindescribed. When the ratio is lower than 0.45 to 2, a brittle, friablesponge is obtained which lacks abrasion resistance and also lackscompressive resistance. On the other hand, when the ratio is between0.45 to 2'and 0.95 to 2, a resilient compression-resistant sponge isobtained. When the sponge is compressed it returns to its previous formwithout destroying the cells.

The amount of water which is added should be sufficient to react withthe diisocyanate groups remaining after the condensation of theglycen'de with the diisocyanate, but preferably not in too large anexcess. When the ratio of -OH to -NCO groups is low, that is, in theregion of from 0.45 to 2 and 0.6 to 2, a larger number of diisocyanategroups will remain unreacted and consequently a larger proportion ofwater may be used. If more water is added than is theoreticallynecessary for reaction with the diisocyanate groups, that water willtemporarily remain in the foam and act somewhat as a plasticizer, andtherefore the use of a large excess is not desirable. If an insufiicientamount of water is added to react with all of the free isocyanategroups, these isocyanate groups are then free to react with other activehydrogens in the resin. Since the reaction of water with twodiisocyanate groups results in the formation of a substituted urea withthe liberation of carbon dioxide, the hydrogens remaining on thesesubstituted urea groups are reactive and any excess isocyanate groupsmay react with those; hydrogens and cross-link. This usually than whenthe amount .of .water.is .sufiicient tomeact with all of the isocyanategroups.

The fatty acid glyceride should have an hydroxyl number not materiallyless than 49, for whenarfatty acid-glyceride having 2 too .low an.hydroxylsnumber is used there is an insufiicient amount of diisocyanateleft'free to react with the water and form the necessary amount ofcarbon dioxide for proper blowing of the sponge. If additionaldiisocyanate should.- be: added to overcome this deficiency, thentheratio ofxnumberstof OH to -NCO groups is too low and a more brittle:and less desirable sponge or cellulargzproductis obtained. Theglycerides having an hydroxyl number up to 180 may of course be used.This top number is not a limitation except from a practical standpointfor'it is thehydroxyl .number .of the pure triglyceride of ricinoleicacid. Naturally occurring oils with a higher hydroxyl number are notknown, and it is difiicult to oxidize unsaturated oils to .an extentWhere products .are produced having abigher hydroxyl number.

A tertiary amine catalyst is preferably used with the water informingthesponge because this accelerates the reaction between the isocyanateand. the water. The catalyst-may be omitted and a longer time of curingmay be used, or elevated temperatures may be used in order tospeedthereaction. Howeveryibis much simpler and more practical to-add thet'ertiarynaminecatalyst to cause the reaction to takeplace rapidly andpermit the "final curing at roomtempenature.

By using substantially the proportions of fatty acid triglycerideamdarylene diisocyamiate given above, a pie polymer is obtained having aviscosity within .the range of from about 750m 75,000 centipoises at 30C. At these viscositiesithe "carbon dioxide' which-is evolved does notescape from the massto anyextent, and stillthe mass is capable of beingproperly blowninto a cellular mass. If the viscosities are .too low, theearbon-dioxide would merely bubble out-andescape, while at=toohigh aviscosity satisfactory amixing-cannot be obtained and nonuniformcellular products :of higher Y density -result.

Often thereisa slightzinitial shrinkage in unsupported foams-whichdisappears .onstanding. This is believed to be a temperatureetfect due-.to..the 'cooling 'of the foam after'curing. Onstanding, air diffusesinto the-cells and they resume .their original'asize.

The following ttertiarysamines arel illustrative of those useful ascatalysts in thisreaction:.triethylamine,diethyl V cyclohcxylamine,.dimethyl rhex-adecylamine, 'dimethyl cetylamin'e tri'ethanolamine,pyridine, Iquinoline, 3- methyl-isoquinoli-ne. The morebasiuaminesappear to be the most effective :as catalysts, and -:those.of relatively low volatility are preferredsoithatzthey will not escapeto an objectionable degree during theireaction ;and so they willnotimpart to the tproducttan-objectionable:odor.

A wide variety of arylene .diisocyan-ates :may be :employed to producethe products of thisinvention. Representative of the types thatmay beuSedLare: tolylene- 2,4diisocyanate, metaphenylene diisocyanate, l'chlorophenyiene-2;4diisocyanate, xcnylene-4,4 diisocyanateandnaphthalene-1,5-diisocyanate. In general, the 'diisocyamates of thebenzene and naphthalene series may :be employed.

It is frequently desirable touse a dispersing agent in the water as itis mixedwith-.the prepolymer. :Usually from .one-halfpercent to onepercentof dispersing agent is sufficient; however,-some=of ithehigher.molecular weight compounds hereinafter mentioned'which'assistin formingthe dispersionalso operate as :modifiersof'zthe resulting cellularplastic material, and-thereforemay be used ;in larger amounts. Among thedispersing agents which have been found to be satisfactory are: sodiumcarb'oxy methyl cellulose, lignin sulfon-ates, lauric:aoid oster oftriethanolamine, gelatine, .diethyhcycl'ohexylamine salt or alkylsulfates containing2from l2itozl6mcarbon"atomsgand the polyalkyleneoxide glycols 'such as polyethylene oxide glycol .or .polypropylene.oxide -glycol, .nrmixturesmf-the two.

Additives such as fillers, extenders, modifiers, etc., may also beincorporatedinto'the material to give various effects to the spongestructure. Generallyspeaking these materials give more rigid,morebrittle :and more dense products. Consequently, when they are usedthey are added in minor amounts. Such. products include magnesiumcarbonate, powdered Wood cellulose, bentonite, silicon dioxide, calciumsilicate, carbon black, glass fiber, magnesium stearate, methylene.distearamideuctc. Magnesium stearate appears to cause somewhat largercell structure and somewhat thicker cell walls.

These'cellular materialshave-insulating properties similar tocommercially available insulating materials but are generallymuch'lighterand consequently offer a considerable saving Where weightisof particular importance. .As will beLillustratedin theexamples, itzis,quite possible to :applythis-type.ofinsulatingtto various;.pieces .ofequipment, pipe..etc., with a minimum amount-of. labor. .For example,.a'.simple cardboard. mold. may be built around thepipe.and.the,plasticmaterial can. be poured .into the mold. Itifoams .upinsidethe mold andLcures in,place. The cardboardmold may then bestripped off and-the .insulat'ion canibeileftas is, or can be painted.

"The material may also .be used to furnish insulation inside a formedbody. For example, a refrigerator .door consists of arr inner .andouterside. The freshly mixed mass may be pouredinto such a compartment.andpermitted to foam up, thereby filling the cavity. Obviously thesecellular plastics maybe molded in any desired shape, or readily cut intodesired shapesfrom preformed blocks or'sheets. This 'foamhas anadvantage over the foams of the prior art in that itis much stronger andless apt to break on compression. In other words,.it :has a resiliencecombined with a resistanceto damagebycompression which the otherplasticcellular materialsdo not have.

PREPARATION OF PREPOIjYMERS Theprepolymeris preparedbymixingthe organicdiisocyanate and i the vhydroxyl containing fatty acid glyceride in avessel and heating to about 70 to-'95' .C. for'from .12 to 30.minutesand then cooling toroom temperature. During this heating itis'essentialthat .thereaction mixture be protectcdfrom atmospheric moistureeither'byuse of'a dryingxagentton theLeXit of the-vessel or bymaintainingzazmoisulre-free atmosphere of an-inert gas such as air or.nitrogen. The. reaction of the two compounds is somewhat cxothermic butnot excessivly=so. A'fter'reaction'stherprepolymer is cooled to'roomtemperatureand then may ibexused'to prep are the foamed plastic. Thefollowingprepolymers were prepared inthe abovemarmer.

A. g. (0.57 mol) 2,4-tolylene diisocyanate 150g. castor oilihydroxylNo.16.1.5)

(-OH to -NCO ratio='0.77 to 2.0)

B. 11215 g. (065 mol) 2,4-tolylene diisocyanate 13715 g. castor oil(hydroxyl.No.16 1.5)

C. "125 ,g. (0I72'mol) '2,4-to1ylenediisocyanate 125 g. castor oil."(hydroxy1INo..l61j5 D. 40 g. (0.23 mol) 2,4-toly1ene diisocyanate 60.g. hydrogenated castor oil, N. W. 950 (hydroxyl E. 30 g. (012 mol)methylene .bis(4 phenyl-isocyanate) 20 g. castor oil(hydroxy1.No..161.5)

F. 18.3 g. (0.105 mol) 2,4-tolylenediisocyanate g. heavy-bodied linseed.oil '(hydroxyl-No. 66.5) (OH'to -NCO ratio-0.95 to 12.0)

The following examples are given to further illustrate the invention.

A Hamilton-'Beach drink mixer was used for mixing together theprepolymer with the water and other ingredients in the followingexamples. Any other machine which gives very efficient and rapidagitation is satisfactory.

Example 1 47 grams of prepolymer A and 3 grams of finely dividedmagnesium stearate were mixed together with the electric mixer. To thismixture was then added 1 gram of Water and 0.9 gram of diethylcyclohexylamine. After stirring for about 30 seconds the mixture assumedthe appearance of whipped cream due to the formation of tiny gasbubbles. This foamy mass was then immediately transferred to a metalmold which was open at the top and which was 4 x 4 x 4 inches. This moldhad previously been coated with a solution of paraffin wax in petroleumether so that the wax could act as a mold release agent. The foamy massreached its maximum volume, which was about 58 cubic inches, within twoto three minutes. After ten minutes standing at room temperature thematerial had cured to a rigid cellular mass with cells ranging indiameter from about 1 to mm. The apparent density of this mass wasbetween 2.8 and 3.1 lbs. per cubic foot. A cross-sectional slab of thismaterial was found to have a thermal conductivity value of 0.4824 B. t.u. per hour per square foot of area per degree Fahrenheit per inch ofthickness.

Example 2 The procedure was the same as Example 1, and the followingingredients were used: 50 g. of prepolymer A, 2 g. of magnesiumstearate, 3 g. of triethanolamine, 0.9 g. of diethyl cyclohexylamine and1 g. of water. The resulting cellular product was semi-rigid with cellsrang ing in size from 1 to 5 mm. in diameter. The density was about 3lbs. per cu. ft.

Example 3 The procedure was the same as Example 1. The ingredients were44 g. of prepolymer C, 5 g. of triethanolamine, 1 g. of water and 0.9 g.of diethyl cyclohexylamine. A pliable and resilient sponge was obtainedwhich had cell sizes of about 1 to 2 mm. in diameter. The density wasabout 4.5 pounds per cubic foot.

Example 4 Example 5 The procedure was the same asin Example 1. 'Theingredients were 45 g. of prepolymer B, 5 g. of lignin sulfonate, 1 g.of water, and 0.9 g. of diethyl cyclohexylamine. The resulting productwas hrown in color and was pliable and resiilent to the touch. It hadsmall, uniform cells of about 1 to 3 mm. in diameter and the density wasabout 2.8 lbs. per cu. ft.

Example 6 The procedure was the same as in Example 1. The ingredientswere 50 g. of prepolymer E, 3 g. of magnesium stearate, 0.45 g. ofdiethyl cyclohexylamine and l g. of water. The resulting product wasrigid and very tough. It was brown in color and had small uniform cells1 to 2 mm. in diameter. The density was about 4.5 lbs. per cu. ft.

Example 7 r The procedure was the same as in Example 1. The ingredientswere 40 g. of prepolymer D, 1 g. of pyridine, and l g. of water. Theresulting material was very rigid and had cells 1 to 3 mm. in diameter.The density was about 6 lbs. per cu. ft. In this example about 4 hourswas necessary before the final cure was complete.

Example 8 The procedure was the same as in Example 1. The ingredientswere 50 g. of prepolymer G, 1.3 g. of water and 0.9 g. of diethylcyclohexylamine. The resulting product had a density of 4.2 lbs. per cu.ft. and was resilient, non-tacky and non-friable. The cell structure wasquite uniform, the cells being about 1 to 3 mm. in diameter.

Example 9 The procedure was the same as in Example 1. The ingredientswere 40 g. of prepolymer F, 4 g. of 2,4- tolylene diisocyanate, l g. ofwater and 0.9 g. of diethyl cyclohexylamine. The cell structure of theresulting material was quite uniform and averaged about 1 to 2 mm. indiameter. It was quite resilient and non-friable.

Example 10 In this example a section of pipe was coated with thematerial as an insulator. The pipe was 27.5 cm. long and 3.2 cm. inoutside diameter and had a flange on each end which was 11 cm. indiameter. A piece of light cardboard lined with polyethylene sheetingwas fitted around the flanges so as to form a closed cylinder. A narrowslot was cut in the top of the cardboard for the addition of the foamingmixture. The foaming mixture was prepared as in Example 1, and theingredients were 101.5 g. of prepolymer C, 3.5 g. of water and 1.5 g. ofdiethyl cyclohexylamine. After stirring, this material was poured intothe slot and allowed to foam around the pipe. After one hour thecardboard and polyethylene were removed, leaving the pipe covered withthe cellular plastic material which had small uniform cells and a smoothand pliant resilient surface. In order to demonstrate the utility ofthis type of product as an insulation, acetone at -55 to 40 C. wascirculated through the pipe for 24 hours. The surface of the foamremained at room temperature. No evidence was detected that the lowtemperature caused brittleness.

Example 11 In a manner similar to Example 10, a pipe 61 cm. long and 4.9cm. in outside diameter with 13 cm. diameter flanges was insulated witha mixture prepared from 492 g. of prepolymer A, 20 g. of magnesiumstearate, 30 g. of triethanolamine, 10 g. of water and 4.5 g. of diethylcyclohexylamine. The product foamed into place around the pipe in thesame manner as that in Example 10, and the covering was resilient andhad cells ranging in size from 1 to 5 mm. in diameter. As the test forinsulation, low pressure steam was circulated through this pipe for 24hours. A thermometer placed at the junction of the pipe and insulationregistered to 94 C. The outer surface of the insulation remained at roomtemperature. The inner portion of the foam became softer and moreplastic at the higher temperature, but did not melt or lose its shape.

Samples were cut from the foams prepared in the above examples andsubjected to testing as hereinafter described. Samples of commerciallyavailable lsocyanate foam products which were prepared according to themanufacturers directions were also tested in the same manner.

Flexural test.--To determine ability to withstand bend ing. A specimenof foam x l x 3 inches was supported flat between pieces of metal 2inches apart and 95 inch high. A metal strip was gently forced down uponthe mid-point of the foam and the foam deflected /2 inch. The specimenof foam either broke before the /2 inch deflection, formeda small crackon the under surface without a complete break, or could be subjected tothe /2 inch deflection without being damaged.

Compr'essl'mz' test.-A- measure of resiliencepthe ability totbccompressed zandzrcgain shape. A one iuchieube of foam was'compressed'to/2 inch :height and allowed-to expand. The height of the cube-was thenmeasured after being released for one hour, then after twenty hours.Wherethe samples recovered, the maximum recovery was attained in thefirst hour. Duplicate samples were run and'the final heights arerecorded in the table.

Impact :rcsr.A lOOOg. weight iwas dropped through a guide tube ofcardboarda distance of '11 inchesitfbottom-.of weightsto1top of 1 "inch:cubesample) onto the sample of foam being tested.

RESULTS OF PHYSICAL TESTS Example .Flexural Test Compression Test,Impact Final Height Test 1 C at :2 deflection NB Linch a N Zflis inch (2NH as, tsinchu .a C at 9 deflection NB 1 inch a O at $4 deflection NB 1inch a C at it, B at $5" deflection. 3s, inch a NH.-. .linch a 8 I\ 1inch a 9. NH. 1 incha 10. H- 1 inch b 11. H ,teinch. a A B at isdcfiection.. .Structuredestroyedc B B at deflection Strueturedcstroyedb1 NB=no break; B=brealr.; C=surfaee crack; NH=not harmed.

2 a=sample not harmed; b=sample compressed to to 9% inch with onlyslight damage to structtu'e: c=sample completely shattered.

A=comtnereial product A.

li=commerciel product L.

As illustrated by theabove comparative tests, the pnodnets of thisinvention show unexpecte'dresilience, flexibility and resistance toimpact. These properties make the new cellular plastic materials ofvalue whereever plastic foams are useful, and particularly. forinsulating'fillings coatings, and the like.

We claim:

1. A cellular plastic material comprisingthe condensation product of anarylene diisocyanate and a fattyacid triglyceride having an hydroxylnumbernotmaterially less than 49, which have been condensed in amountssuch that the ratio of the hydroxyl groups contained in the fatty acidtriglyceride 'to'the number of isocyanate groups in the arylenediisocyanate .is between 0.45 and 0.95 to 2, reacted with anamount ofwater so as to provide about one mol of Water per two unreactedisocyanatc groups .in the condensation mass.

2. A cellular plastic material comprising the-water reaction product ofan arylene diisocyanate-castor oil .condcnsation product in which all ofthe hydnoxyl groups of the castor .oil have been reacted with thearylene diisocyanate but in which from 52.5% to 77.5% of theisocyanategroups of the .arylene diisocyanate were unreacted prior to the reactionwith water the amount of water reacted with the condensationproductbeing an amount so as toprovidc about one mol of water per twounreaeted.isocyanategroupsin the condensation product.

A composition comp'risingfthe condensation product of a 'hlown dryingoil having anhydroxyl number not materially less. than 49, said oil.being sclectedirom. the group "consisting of'linseed oil,tung oil,poppyseed oil, 'hempseed oil and soyaoil, and a sufiicient amount'of anarylene diisocyanate to react with all the hydroxyl groups containedz insaid oil'butdcavingirom 52.5% to 77.5% of theisocyanate-groups :ofthe'arylene diisocyanate un reacted.

4..A compositioncomprising the condensation product of castor oil anda-sufiicient amount of an arylene diisocyanate .to.react with all (thehydroxyl .groups contained in the castor .oilrbut leavingfroni 52.5% to77.5% .of the isocyanate groups of thezarylene diisocyanate .unreacted.

.5. .Aprocesstfor producing cellular plastic :material which comprises;condensing an arylene .diisoeyanate and afatty acid triglyceride havingan hydroxyl numbcrinot materially less than 49, in amounts such that theratio of thehydroxyl ,groups .contained in the fatty acid triglycerideto the number of isocyanate groups in the .arylene diisocyanateisbetween 0.45 and 0.95 to 2, and reacting this condensation produet withan amount of watersoas to .provideabout one mol of water per two'unreactedisocyanate groups in the condensation product.

-6. "In a process for preparing a cellular plastic .matcrial, thestepwhich comprises condensing a fatty acid triglyceride having an hydroxylnumber not materially less than 49, with a sufiicient amount of anarylene diisocyahate to .react with all the 'hydroxyl groups present inthe .fatty acidptriglycerideand have remaining in thecondensationproduct from 52.5% to 77.5% of the isocyanate .groups'of thear-ylene diisoeyanate unreacted.

7.'In a processIfor preparing a cellular plasticmatcrial, the. stepwhich comprises condensing a .blown drying oil having an hydroxylnumbernot-materially less than 49,

said oil'being selected from the group consisting of linseed oil, tungoil, poppyseed oil, hempseed oil and soya oil, with a suflicientamount-of an arylene diisocyanate to react with all .the hydroxyl groupspresent in said oil and haveremaining in the condensation product from52.5% to77.5% of the isocyanate groups of the arylene diisocyanateunreacted.

-'-8.I11 a process for preparing a cellular plastic .material, the stepWhichcomprises condensing castor oil with a sufiicient amount of anarylene diisocyanate to react with all the hydroxyl groups present insaid oil and have remaininginthe condensation product from 52.5%to"77.'5% .of the isoeyanate. groups of the arylene diisocyanateunreacted.

References Cited in thefile of this patent UNITED STATES PATENTS2,577,279 Simone-t al Dec. 4, 1951 2,602,783 .Simon et al July 8, 19522,650,212 'Windemuth Aug. 25, 1953 OTHER REFERENCES .ChemicalEngineering, vol. 57, No. 4, pages and I66.

1. A CELLULAR PLASTIC MATERIAL COMPRISING THE CONDENSATION PRODUCT OF ANARYLENE DIIOCYANATE AND A FATTY ACID TRIGYLCERIDE HAVING AN HYDROXYLNUMBER NOT MATERIALLY LESS THAN 49, WHICH HAVE BEEN CONDENSED IN AMOUNTSSUCH THAT THE RATIO OF THE HYDROXYL GROUPS CONTAINED IN THE FATTY ACIDTRIGLYCERIDE TO THE NUMBER OF ISOCYANATE GROUPS IN THE ARYLENEDIISOCYANATE IS BETWEEN 0.45 AND 0.95 TO 2, REACTED WITH AN AMOUNT OFWATER SO AS TO PROVIDE ABOUT ONE MOL OF WATER PER TWO UNREACTEDISOCYANATE GROUPS IN THE CONDENSATION MASS.